In many developed countries an increasingly affluent society is able to pursue recreational activities such as touring, camping, boating and the like with purpose designed mobile vehicles or trailer-borne units towable behind a motor vehicle. Motor homes, trailer homes, camper trailers and trailerable boats all provide a wider range of choices of recreational venues than a permanent holiday residence, fixed vessel mooring or the like.
While providing a user with a greater geographical freedom, mobile or trailer-borne recreational units tend to be purpose designed for a specialized sole function or otherwise represent a poor compromise between differing functionalities. For those persons who wish to enjoy boating and comfortable accommodation at a remote location, this often necessitates the expense and inconvenience of having to tow multiple units with separate tow vehicles or otherwise to utilize, say, a large motor home to tow a large boat/trailer combination which can be quite daunting for inexperienced drivers.
For several decades, various proposals have been made for amphibious vehicles which can be used as a water-borne vessel offering various levels of accommodation/shelter while offering the same accommodation/shelter on land.
U.S. Pat. No. 4,869,194 discloses an amphibious accommodation unit transportable on a flat bed trailer wherein the unit includes a main accommodation unit incorporating a main hull and a second hull pivotally mounted to the main unit to form a hull extension in an extended state.
U.S. Pat. No. 6,663,130 discloses a pontoon boat/trailer combination wherein the trailer wheels are located between the fixed pontoons of the pontoon boat.
U.S. Pat. No. 5,072,963 discloses a combined trailer home and boat assembly wherein the trailer includes a superstructure surrounding the front and side portions of the boat when supported on the trailer to present the appearance of a unitary, aerodynamically designed structure when used as a trailer home.
U.S. Pat. No. 6,164,238 describes a dual hulled boat with a frame connecting the spaced hulls. A hinged connection in the frame allows the hulls to be locked in an open extended state or in a folded state wherein one hull is located above the other hull in an inverted state to form an enclosure for storage or accommodation.
While generally satisfactory for their respective intended uses, the abovementioned boat/trailer combinations have a maximum permissible width for road use without a special transport license. In Australia, that width is 2500 mm. As a consequence, the limited beam of the vessel can cause stability problems on water or, in the case of the trailer described in U.S. Pat. No. 6,663,130, the narrow track of the trailer wheels could contribute to instability on the road.
Attempts to combine a marine vessel with a separate storage or accommodation unit often give rise to compromises in functionality and/or ease of use.
For example, U.S. Pat. No. 6,293,220 describes a vehicle trailer having a moulded plastics body with a removable moulded plastics cover in the form of an inverted dinghy while U.S. Pat. No. 5,505,514 discloses an elongate trailer frame with a gooseneck trailer hitch, the front portion of the trailer frame supporting a fixed accommodation enclosure while the rear end is adapted to support a boat or motor vehicle. U.S. Pat. No. 4,188,056 describes a trailer frame adapted to support a boat such as a runabout with a retractable roof camper body mounted over the boat. When the boat is removed from the trailer, the camper body may be lowered onto the trailer bed for use as a camper trailer.
It is also known to adapt the structure of a marine vessel to allow the vessel itself to form a trailer frame with retractable and/or releasable ground wheels and a trailer hitch. U.S. Pat. No. 6,568,344 describes a boat/trailer assembly wherein the boat is fitted with at least one longitudinal strut and at least one transverse strut to which may be removably mounted a trailer hitch assembly and spaced road wheel assemblies respectively. Similarly, U.S. Pat. No. 6,446,569 describes a boat hull having wheel mount legs pivotally connected on opposite upper sides thereof for movement through 270° from a retracted stored position in respective hatches to an extended locked position with the wheels engaging a ground surface. An extendable tow bar with a trailer hitch is telescopically mounted to a central region of the boat.
U.S. Pat. No. 6,145,465 describes a combination foldable camper/boat trailer/trailer system wherein a pair of shells are hingedly connected in a clam shell configuration to form a boat hull when fully extended with a collapsible tent structure spanning the two shells. Extendible supports associated with the trailer support the shells in an open extended position.
U.S. Pat. Nos. 4,040,134 and 6,067,925 each describe collapsible pontoon boat assemblies with retractable ground-engaging wheels which permit the vessel to function as an integrally formed trailerable unit when in a collapsed state.
U.S. Pat. No. 4,048,685 describes a trailerable houseboat comprising a travel trailer module and a pair of buoyant pontoons pivotally mounted thereto for movement between a retracted road travel position on the roof of the trailer module and an extended position along opposite lower sides of the module. In a launch position, the road wheels of the trailer module extend below the pontoons to allow the unit to roll on its wheels and when afloat, the travel trailer module is elevated with respect to the pontoons to raise the road wheels up out of the water.
U.S. Pat. Nos. 6,298,802, 6,647,913 and 7,171,915 each address the conflict between vessel stability when buoyant and width limitations for trailer transport by providing collapsible pontoon boats. U.S. Pat. Nos. 6,298,802 and 6,647,913 describe collapsible deck structures which permit pontoons to be moved laterally between an extended position for use on water and a retracted position for road transportation. Both of these patents also describe trailers with transversely movable pontoon supports to facilitate movement of the pontoons between extended and retracted positions on the trailer. U.S. Pat. No. 7,171,915 describes a pontoon boat with inflatable pontoon envelopes collapsible to reduce transverse width of the vessel for road transportation while an extendable deck section is retractable to reduce transportation length.
While each of the aforementioned amphibious recreational units are, to a greater or lesser extend, generally satisfactory for their respective intended purposes, each suffers from one or more deficiencies such as complexity, cost, requirement for a large horsepower towing vehicle, stability under towing or afloat, lack of convenience for use as an accommodation unit, inadequate performance as a marine vessel and the like.
Accordingly, it is an aim of the present invention to provide a multifunctional recreational vehicle which overcomes or ameliorates at least some of the deficiencies of the prior art and/or otherwise to provide consumers with a greater choice.